Marmoleum is my preferred choice of floor covering - really lovely stuff but can need heaps of self-levelling Ardit or a chipboard/plywood subfloor as it will expose every tiny imperfection in the floor surface. I am going to get some in the horsebox - softer and warmer than wood or vinyl and longer lasting (than vinyl, which I have in my kitchen at home).

I've done two polished concrete floors in the kitchens of our last two houses and they look great and are very durable but it's a lot of dicking around with noxious chemicals and tons of dust to get a good finish.

Concrete is porous so you have to apply a densifier to the surface then machine polish it then seal it. You can just paint it and it might look acceptable for about ten minutes but it won't last.

Given the area you have, I'd stabilise and level the old floorboards and then do a bamboo floor over the whole lot. The areas are too small for different finishes IMO.

Depends on costs but I'd be inclined to carpet or tile the lot....
Plenty underlay mind....if you opt for carpet.
Tiling will probably require some levelling compound and it's messy and not a cheap option.....
I'd be looking at either carpet or laminate again....or vinyl

It’s probably a concrete pour but it might be a fairly thin sand & cement mix that’s been used as a leveller so it’s worth drilling in to check the thickness, you might get a pleasant surprise and find that it comes up quite easily in which case you can level off and lay new boards in that area, then sand the others.

From the pic it looks like the whole area would need a lot of prep before it would be suitable for tiling, and you’d need to use a decoupling membrane to avoid cracks if you’re tiling over two different subfloors.

Laying new laminate or wood over the existing would mean replacing the skirting if you wanted a clean finish, or installing beading around the perimeter to cover your expansion gap.

We are having a few house things done that include new kitchen floor & in the space next to it which used to be a downstairs bathroom. None of the floors are level from hall to lounge to kitchen to old bathroom.

We had a quote for Amtico for kitchen & old bathroom but they don't make that exact one anymore. The current plan is to fit Coretec in the lounge, kitchen & old bathroom as they all flow into each other & no door between them. We are going to ask how much to do the hall too but first pref is to have the hall different.

When we started the lounge was not part of the work and now there is the bloody hall.